setting data attributes in html not working

Setting a data attribute using attr throws TypeError: Cannot read property 'test' of undefined.

Example

$('ul').attr('data-url', 'http://www.example.com');

Error Stack

TypeError: Cannot read property 'test' of undefined
    at Object.$.each (D:\node\frix\lib\html-creator.js:141:39)
    at exports.each (D:\node\frix\node_modules\cheerio\lib\api\traversing.js:300:24)
    at HTMLCreator.insertContent (D:\node\frix\lib\html-creator.js:131:12)
    at HTMLCreator.resolveElements (D:\node\frix\lib\html-creator.js:56:10)
    at promises.push.access.readElement.then.template (D:\node\frix\lib\html-creator.js:113:23)
    at tryCallOne (D:\node\frix\node_modules\promise\lib\core.js:37:12)
    at D:\node\frix\node_modules\promise\lib\core.js:123:15
    at flush (D:\node\frix\node_modules\asap\raw.js:50:29)
    at _combinedTickCallback (internal/process/next_tick.js:67:7)
    at process._tickCallback (internal/process/next_tick.js:98:9)

[drsnyder]

I was also tripped up by this. According to the documentation, one would think that setting data attributes is possible with data.

The snippet for data() reads:

Method for getting and setting data attributes. Gets or sets the data attribute value for only the first element in the matched set.

So I was surprised when element.data('key', 'value') doesn’t change the value.

[garyee]

@drsnyder even if it says something else in the documentation, it is standard jquery behavoir, took me some time to figure out.